Assumption: Breaking the bag of waters (amniotomy) will shorten labor by getting things moving.
This review of studies shows no difference in the length of the first stage of labor (all labor prior to pushing) between women who had amniotomy and those who allowed their water to break on its own.
Breaking a woman’s bag of waters prematurely does carry risks, the scariest of which is a prolapsed cord. Since these studies show little benefit in terms of moving labor along, it is definitely worth a conversation with your caregiver before deciding on this procedure. My own personal story is that I did opt for amniotomy in my fourth pregnancy and I truly believe it was the right decision in that circumstance. (If you want the whole story, I’m happy to share. Shoot me an email! firstname.lastname@example.org) This experience showed me that the procedure can be valuable, but it is not something that should be routine and women should know that evidence does not show that it will speed labor as many hope it will!